Highly efficient blue top-emitting device with phase-shift adjustment layer

The phase shift on the reflection from a semitransparent electrode of a top-emitting organic light-emitting device is utilized in this paper to realize a deep blue emission with high efficiency. The phase shift could be adjusted by changing the thickness of Alq(3) when it was deposited onto the semitransparent electrode of the device. Through simulation it is found that the blue shift of the resonant wavelength occurs in a certain range, which is concerned with Alq(3) thickness and the cavity length between two reflective electrodes. According to the simulation, a blue top-emitting organic light-emitting device with a designed structure was demonstrated experimentally by using such a phase-shift adjustment layer. Finally, the device showed excellent performance both in efficiency (3.4 cd/A at 8 V) and Commission Internationale de l'Eclairage coordinates (0.13, 0.15). The brightness of the device reached 20 000 cd/m(2).